The present application claims priority from Japanese Patent Applications Nos. Hei. 10-320577 filed on Nov. 11, 1998, Hei. 11-235246 filed on Aug. 23, 1999 and Hei. 11-301447 filed on Oct. 22, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an ink jet type printing apparatus which is supplied with ink from detachable ink cartridge and ejects ink droplets from a nozzle aperture of a print head to a recording medium, and to an ink cartridge suitably installed in the ink jet type printing apparatus. More particularly, the invention relates to an ink cartridge provided with a memory device for writing and reading information relating to the ink contained therein, to an ink jet type printing apparatus which installs thereon the ink cartridge capable of controlling access to the memory device of the ink cartridge, and to a method of controlling the same.
2. Related Art
Generally, an ink jet type printing apparatus is provided with a print head which supplies drive signals to a piezoelectric transducer or heating means in response to print data, and pressurizes the ink by the energy generated by the piezoelectric transducer or the heating means to thereby eject ink droplets from nozzle apertures, and with an ink cartridge accommodating the ink to be supplied to the print head.
The print quality is determined by the resolution of the print head such as size or diameter of each of the nozzle aperture and the number of the apertures. In addition to the resolution of the print head, the print quality is also influenced by the type, or specification of ink or, for example, viscosity of ink. Further, the print quality is also determined by the bleeding condition of ink ejected on a recording medium. Therefore, the ink characteristics has been improved to enhance the print quality, or the driving operation for the print head has been improved to perform an optimum print quality for the particular ink characteristics even if the printing apparatus installs a conventional type of ink. Furthermore, the head maintenance condition has also been improved with respect, for example, to the cyclic period of the cleaning operation or the flushing operation to prevent the nozzle apertures from clogging.
Thus, the print quality of a printing apparatus can be improved as a whole only when the combination of the ink characteristics with the appropriate driving operation for the print head is improved, not only by the ink characteristics. The result of such technical development can be reflected on newly manufactured ink jet type printing apparatuses before shipping to the marketplace. However, such technical development would be practically impossible after the printing apparatus is shipped, because the printing apparatus has to be brought to a service center, and the memory means which records the control data for the printing apparatus would have to be exchanged.
In view of the difficulties as described above, as disclosed in Japanese Patent Publication No. 2594912, there has been proposed a printing apparatus which employs an ink cartridge provided at a surface thereof with a non-volatile rewritable memory, and data stored in the memory indicating the residual ink is read out by the printing apparatus for controlling the printing operation.
In addition, there has been proposed another process for controlling the print operation of an ink jet type printing apparatus in accordance with information recorded in a memory element disposed on an ink cartridge. For example, published Unexamined Japanese Patent Application (OPI) No. 6-126981 discloses an ink cartridge which is provided with a memory element such as an electrically erasable and programmable read only memory, or EEPROM. The memory element previously stores information relating to the print control, and the printing apparatus reads out information and utilizes it to control printing and also writes data of, for example, residual ink calculated by the printing apparatus.
The conventional printing apparatuses as described above may be operated under an optimum condition by adapting the print control to information relating to the residual ink. However, in a case where a user treats the printing apparatus inappropriately, for example, if the power is shut down roughly without proceeding through a designed power-off process which is not expected by the manufacturer, data of the consumed amount of ink cannot be written in the memory of the ink cartridge, which may result in causing a big difference of residual ink amount according to data stored in the memory element from that of the real ink cartridge. Further, the same problem would occur when an accident happens such as, for example, an inevitable blackout or when the power socket of the printing apparatus is accidentally pulled out of the outlet by entangling user""s or other person""s feet in the power line.
On the other hand, the conventional printing apparatus may accompany another problem as follows. The rewritable memory means which does not require power for holding the stored data requires longer time for writing data to or reading from the memory means. Therefore, frequent writing and reading data would deteriorate the throughput of the printing operation. Specifically, when data is written in the memory means during a printing operation, a central processing unit of the printing apparatus is given a heavy workload because it has to process both the print control and the data writing control at the same time. In addition, normally the data writing operation is performed after moving the ink cartridge on a carriage to a predetermined position which takes time. Further, in case of employing a non-contact type semiconductor storage means, reading and writing data takes longer time than the other type of the memory means, and the decreased throughput of a non-contact type semiconductor storage means more seriously degrades performance. As a result of the above problems, the conventional printing apparatuses having memory means would raise a problem in much lowering the print speed.
On the other hand, there are generally two different carriage types of ink jet printing apparatus, i.e., an on-carriage type in which an ink cartridge is mounted on a moving carriage provided with a print head on one hand, and an off-carriage type in which an ink cartridge is mounted on a fixed part of the printing apparatus apart from a moving carriage. According to the on-carriage type printing apparatus, since the ink cartridge is located adjacent to the print head the memory device may be affected adversely by noise generated by drive pulse signals when the print head is driven. For example, data may be changed or damaged if the memory device receives the noise while the printing apparatus reads data from or writes data in the memory device. Such a problem is more serious in case of a semiconductor memory device of a non-contact type which employs electro-magnetic signals because the drive signals for the print head would propagate strongly in the air and may be interposed as a noise on the electro-magnetic signals supplied to the memory device.
The present invention was made in view of the foregoing difficulties and problems accompanying the conventional ink jet type printing apparatus.
An object of the present invention is to provide an ink jet type printing apparatus capable of assuredly writing and reading data relating to ink in and from a memory device attached on an ink cartridge without deteriorating the throughput of the printing speed of the printing apparatus.
Another object of the present invention is to provide a method of controlling an ink jet type printing apparatus to assuredly write and read data relating to ink in and from a memory device attached on an ink cartridge without deteriorating the throughput of the printing speed of the printing apparatus.
Further, it is also an object of the present invention to provide an ink jet type printing apparatus capable of assuredly writing data relating to ink in a memory device of an ink cartridge even if power is shut down suddenly due to an unexpected accident or user""s error.
Furthermore, it is an object of the present invention to provide a method of controlling an ink jet type printing apparatus to assuredly write data relating to ink in a memory device of an ink cartridge even if power is shut down suddenly due to an unexpected accident or user""s error.
It is still another object of the present invention to protect data to be read or written from or in a memory device attached to an ink cartridge from noise which may be generated when driving a print head.
The above and other objects can be achieved by a provision of an ink jet type printing apparatus which, according to the present invention, includes: a print head having nozzle apertures from which ink droplets eject; an ink cartridge containing ink supplied to the print head; a memory device attached to the ink cartridge, the memory device storing information relating to ink contained in the ink cartridge; and an access control device for controlling access to the memory device for reading data from and writing data in the memory device, the access control device allowing the access to the memory device only when the printing apparatus is in non-printing status.
According to the invention, the non-printing status of the print head may be caused either by a power off instruction signal operated by a user, forcibly shutting down the printing operation, or accidentally or inevitably shutting off a power.
The ink jet type printing apparatus according to the invention may further include an auxiliary battery for supplying power to the apparatus when the accidental or inevitable power shut-off happens.
Further, according to the invention, the memory device may be constituted by either a contact type non-volatile memory, a non-contact type non-volatile rewritable memory, or an electrically rewritable semiconductor storage device.
According to the invention, the memory device is turned off when the print head is driven to perform a printing operation.
In the ink jet type printing apparatus according to the invention, the ink cartridge may include a first ink cartridge containing black ink and a second ink cartridge containing a plurality of different color inks. The memory device may include a first memory device for the first, black ink cartridge and a second memory device for the second, color ink cartridge.
Further, according to the invention, the access control device includes: a read/write section for reading data from and writing date in the memory device; a residual ink amount detection and judgement section for calculating out a ink amount consumed by the print head; and a control section for operating the read/write section to perform a read/write operation, while the printing apparatus is in non-printing status, in accordance with information relating to calculated residual ink receiving from the residual ink amount detection and judgement section. The access control device counts number of the write operation with the memory device, and the memory device is disposed on the ink cartridge at a position adjacent to the print head.
On the other hand, the above and other objects can also be achieved by a provision of a method of accessing a memory device attached to an ink cartridge for storing information relating to ink for use in an ink jet type printing apparatus having a print head. Information is written in or read from the memory device only when the printing apparatus does not drive the print head.
According to the invention, information is read from or written in the memory device after a power off instruction signal is input and before actually turning off a power to the printing apparatus. Further, information read from or written in the memory device either after a printing operation is forcibly shut down, after a power to the printing apparatus is accidentally, inevitably shut down and before the power is actually turned off. According to the invention, the power to the printing apparatus may be supplied from an auxiliary battery after the power is actually turned off.
Still further, the above and other objects can also be achieved by a provision of a method of controlling an ink jet type printing apparatus having a print head and an ink cartridge provided with a memory device for storing information relating to ink, including steps of: turning on a power to the printing apparatus; accessing the memory device and reading out information stored therein; judging whether a head maintenance operation is necessary; proceeding the head maintenance operation if it is judged to be necessary; and accessing the memory device and writing new information therein. The control method according to the invention may further includes steps of: turning on a power to the memory device immediately before the step of accessing the memory device and reading out information; and turning off the power to the memory device immediately after the step of accessing the memory device and writing new information.
According to another aspect of the invention, the above and other objects can also be achieved by a provision of a method of controlling an ink jet type printing apparatus having a print head and an ink cartridge provided with a memory device for storing information relating to ink, including steps of: inputting an instruction replacing the ink cartridge; accessing the memory device of the ink cartridge and writing information in the memory device; moving a carriage on which the print head is mounted to a position where the ink cartridge is to be replaced; taking place the replacement of the ink cartridge; accessing the memory device of an ink cartridge newly installed in the printing apparatus; introducing ink contained in the new ink cartridge to the print head; finishing the ink introduction; and accessing the memory device. The method according the aspect of the invention may further includes steps of: turning on a power to the memory device immediately before each of the steps of accessing the memory device; and turning off the power to the memory device immediately after each of the steps of accessing the memory device.
According to still another aspect of the present invention, a method of controlling an ink jet type printing apparatus having a print head and an ink cartridge provided with a memory device for storing information relating to ink, includes steps of: accidentally or inevitably shutting down a power to the printing apparatus; accessing the memory device of the ink cartridge and writing information in the memory device; and actually turning off the power to the printing apparatus. In this aspect of the invention, the control method may further includes steps of: turning on a power to the memory device immediately before the step of accessing the memory device; and turning off the power to the memory device immediately after each of the steps of accessing the memory device. The control method according to the invention may still further includes steps of supplying a power to the printing apparatus from an auxiliary battery after the step of accidentally or inevitably shutting down a power to the printing apparatus.
According to the invention, data relating to ink such as residual ink is written in and readout of the memory device, which requires a certain time, only when the non-printing status is detected during the printing process. Therefore, the printing operation can be controlled with high reliability in accordance with data stored in the memory device without deteriorating the throughput of the printing speed of the printing apparatus.
Further, according to the invention, data can be written assuredly in the memory device even in a case where a power to the printing apparatus is suddenly shut off without through the designed power-off process by a user who treats the apparatus inappropriately or the power is shut off due to a blackout or when the power socket of the printing apparatus is accidentally pulled out of the outlet by entangling user""s or other person""s feet in the power line.
Furthermore, since the throughput is not lowered as the memory device is accessible only when the printing apparatus is in a non-printing status, the apparatus can employ even the non-contact type memory device, such as electro-magnetic type or opto-magnetic type memory device.
Moreover, because data is written in the memory device only when the printing apparatus is in a non-printing status, i.e., when no drive signal is supplied to the print head, data to be written in the memory device never suffer from the problem of noise which is generated by the drive signals to the print head particularly in case of a on-carriage type printing apparatus in which the memory device attached to the ink cartridge is located adjacent to the print head. Therefore, accurate data can be held in the memory device.